1. Field of the Invention
The present invention relates to an apparatus for reproducing contents recorded on an information storage medium in an interactive mode, and more particularly, to a recording and/or reproducing apparatus capable of reproducing Audio Video (AV) data in an interactive mode, a method of managing an Enhanced AV (ENAV) buffer installed in the recording and/or reproducing apparatus, and an information storage medium having information used to manage the ENAV buffer in the interactive mode.
2. Description of the Related Art
Digital Versatile Discs (DVDs) which support an interactive mode to reproduce Audio Video (AV) data in the interactive mode in a Personal Computer (PC) environment have been on the market and will be referred to as interactive DVDs. The interactive DVD contains markup documents as interactive data for supporting interactive functions as well as the AV data according to a conventional DVD-Video standard. The AV data recorded on the interactive DVD can be displayed in two modes. One mode is a video mode in which an AV picture is displayed in the same form as a general DVD-Video. The other mode is an interactive mode in which both an AV picture and a markup document are displayed in a manner that the AV picture is embedded in the markup document. For example, where the AV data is a movie title, a corresponding movie is shown in a display on an AV picture area and various additional information (such as a scenario of the movie, pictures of casts, etc.) is displayed on the remaining area of the display except for the AV picture area.
The additional information can be displayed in synchronization with the movie title (AV data). For example, when a specific actor appears, a markup document containing the actor's personal history information is required and displayed. Furthermore, the markup document displayed in the interactive mode allows interaction with a user. For example, if the user presses a button made on the markup document, there is displayed the history information of an actor appearing on the AV picture being presently reproduced.
However, in consumer devices (for example, a home DVD player) capable of reproducing the interactive DVD (i.e., capable of supporting an interactive mode), a problem exists in buffer management for supporting the interactive mode. FIGS. 1A and 1B are reference views for easily explaining a problem in a conventional technique.
Referring to FIG. 1A, a conventional Personal Computer (PC) 5 includes a main buffer 55 with a capacity of hundreds of megabytes or more (for example, 256 MB). The PC 5 further includes a hard disk 56 as an auxiliary buffer with a capacity dozens of gigabytes or more (for example, 32 GB). Accordingly, when the PC 5 tries to receive data from a server 9 over the Internet, there scarcely occur cases where the data is not received due to space limitation of the buffer 55 or 56 for storing the data.
However, as shown in FIG. 1B, a home DVD player 2 which is connected to and used with a television 1 has a lower buffer capacity as compared to the PC 5. The buffer capacity is generally only a buffer 25 with a capacity of dozens of megabytes (for example, 32 MB). Accordingly, when the home DVD player 2 tries to access the server 9 over the Internet and receive desired contents, the home DVD player 2 cannot accommodate the contents if the server 9 provides the contents using a method in which contents are stored in a buffer without limitation as in the PC 5.